Temporal structure of letter groups and span of perception

The span of perception for letter groups depends on number of letters presented, length of presentation and structure of the groups. The experiment reported varied the temporal structure of the groups, leaving the total number of letters constant. Groups of 12 letters were presented as a whole or in two or more successive “units.” The total time of presentation was 1-5 sec. In the first experiment each unit was visible until the next appeared, in the second experiment units were visible only during 1/4 sec., although intervals between successive units were kept constant.

The following conclusions emerged:

(a) The visual presence of units did not affect the reproduction for durations over 0.25 sec., except in the 12-letter presentations.

(b) 2×6 letters gave better results than either simultaneous presentation or other divisions; temporal separation was 0.75 sec.

(c) Higher order approximations to Dutch have more influence on 3 × 4, 2 × 6 and 1 × 12 letters than on 4 × 3 and 6 × 2 letters.

(d) A serial order effect exists: central units are reproduced less well than first and last units.

It is suggested that handling a fixed amount of information within a fixed period is limited on the one hand by confusion between simultaneous elements and on the other hand by the interaction between successive units presented too rapidly to allow for proper operation of immediate memory.

The difference between span of perception and span of memory is stressed.     

Information relevance, working memory, and the consideration of alternatives

People routinely focus on one hypothesis and avoid consideration of alternative hypotheses on problems requiring decisions between possible states of the world--for example, on the “pseudodiagnosticity” task (Doherty, Mynatt, Tweney, & Schiavo, 1979). In order to account for behaviour on such “inference” problems, it is proposed that people can hold in working memory, and operate upon, but one alternative at a time, and that they have a bias to test the hypothesis they think true. In addition to being an ex post facto explanation of data selection in inference tasks, this conceptualization predicts that there are situations in which people will consider alternatives. These are:

1. “action” problems, where the alternatives are possible courses of action;

2. “inference” problems, in which evidence favours an alternative hypothesis.

Experiment 1 tested the first prediction. Subjects were given action or inference problems, each with two alternatives and two items of data relevant to each alternative. They received probabilistic information about the relation between one datum and one alternative and picked one value from among the other three possible pairs of such relations. Two findings emerged; (1) a strong tendency to select information about only one alternative with inferences; and (2) a strong tendency, compared to inferences, to select information about both alternatives with actions.

Experiment 2 tested the second prediction. It was predicted that data suggesting that one alternative was incorrect would lead many subjects to consider, and select information about, the other alternative. For actions, it was predicted that this manipulation would have no effect. Again the data were as predicted.     

Selective strategies in the assimilation of successively presented signals

It is found that performance in experiments on the psychological refractory period is highly affected by instructions. In the present experiment subjects were instructed either to handle the signals successively or to group them. Both instructions were obeyed. This seems to indicate that the human organism has various strategies available. Which strategy is actually applied is likely to depend on the structure of the experimental situation, and partly also, on momentary preference. This may explain the variety of results in the literature on this subject.

Finally, it is found that, when two signals are presented simultaneously, the total reaction time is considerably shorter if the signals are “grouped” than if they are “handled successively.” This difference disappears at interstimulus intervals of 0.2 sec. and 0.4 sec. The hypothesis is put forward, that the gain in time at the former case is due to simultaneous perceptual processing of the signals.     

Phenomenal causation at a distance

The aim of this research was to study the finding by Michotte, that a moving object A can apparently produce movement in a projectile B without making contact with it.

The experiments confirm the existence of a causal impression of “pushing at a distance,” but they demonstrate that the greater the distance the smaller the chance that this impression will occur.

When it does, in fact, occur, it has the same characteristics, and is associated with the same experimental conditions, as the impression of “pushing with contact.”

Temporal continuity must obtain between the stopping of the moving object and the starting of the projectile; this refutes any theory positing that there is a “passage” of movement from one object to the other. The effects of differences in speed of movement, whether absolute or relative, are similar in both instances.

In general, however, it appears that distance slightly accentuates the segregation of the movements and that the temporal and kinematic conditions of integration require to be more favourable in the case of distance, if an impression of pushing is to be given which is as satisfying as that found in the case of direct contact.

The size of the Radius of Action, that is, the extent of the passive phase of the projectile, is of the same order in the two cases.

The results bring out the fundamentally temporal-kinematic nature of the perceptual pattern of pushing. They appear difficult to reconcile with an interpretation based on past experience, but tally with the theory of “Ampliation of Movement” put forward by Michotte. According to this theory the essential point lies in the phenomenal transitory belonging to A (the moving object) of the movement performed by B (the projectile).     

Frustration and stereotyped behaviour in human subjects

The investigation was designed to show the effects upon behaviour of three different durations of frustration, and two degrees of motivation during the frustrating period. Frustration was induced in 144 subjects by setting them the task of “learning” an insoluble temporal maze; they had to record their responses by pressing on one or other of two morse-type keys. Its effect was measured in terms of:

(1) The time taken to learn a soluble maze introduced, without the subjects' knowing it, by changing the system of “rewarding” responses from one based on chance to one based on the constant repetition of a pattern requiring the responses: Left—Right—Right, for its solution.

(2) The tendency for the subjects to show stereotypy of behaviour by responding on the same key for a number of trials in succession without reaching a solution.

(3) The pressure exerted on the response keys, which was taken to be a measure of vacillation.

Predictions that the time taken to learn the soluble task, and the stereotypy, would increase in direct relation to the duration of the frustrating period and the degree of motivation were tested.

It was found that, while there was an immediate increase in both the time taken to learn the soluble task and the stereotypy after a short period of frustration, a point was reached under conditions of prolonged frustration after which no further increase occurred and some adjustment to the situation was shown.

Some confirmation of the effect of increase in motivation in the direction predicted was obtained in all cases, but the differences were not statistically significant. The rankings of the subjects according to the time taken to learn the soluble task and the degree of stereotypy were found to be closely correlated. A definite tendency towards increased vacillation of response was seen in many of the records during the period when frustration might have been expected to have been at its peak.

These findings are discussed in relation to Maier's theory of frustration and to Selye's concept of a “general adaptation syndrome.” The latter theory is more suitable for the interpretation of the results of the present investigation.     

A further study of the pendulum phenomenon

A first series of experiments had demonstrated certain conditions eliciting or inhibiting a “pendulum” phenomenon in the visual perception of apparent movement. The present study consists of five further variations designed to show more clearly conditions of occurrence and non-occurrence of this type of movement. The main findings are:

(i) Altering the axis of display to vertical significantly reduces the frequency of pendular-movement perception;

(2) Altering the position of metronome from behind to the side of the visual display, gives results almost identical with those where the metronome was inaudible, but, when the metronome is illuminated in this position, all forms of movement perception are reduced, and no pendular movement is reported.

The results for all the ten conditions, including the five of the first series are summarized, and the following possible factors are discussed: past experience, physiological nystagmus, and intervening adaptation. All three may be required to account for the perceptual phenomena under investigation and the dichotomizing of explanations into “experiential,” or “physiological,” appears to be arbitrary and inconsistent with the complexity of the observed facts.     

Book reviews

Timing in Temporal Tracking. By J. A. Michon. Soesterberg, Netherlands: Institute for Perception RVO-TNO, Netherlands. 1967. Pp. 127.

Human Performance. By Paul M. Fitts and Michael I. Posner. Belmont, California: Brook/Cole Publishing Co. 1967. Pp. x + 162. 14s.

Human Memory. By Jack A. Adams. New York: Mcgraw Hill. I967. Pp. ix + 326. $9.50.

Biological Foundations of Language. By Eric H. Lenneberg. With Appendices by Noam Chomsky and Otto Marx. New York and London: Wiley. 1967. Pp. xvi+489. £6.

The Genesis of Language: A Psycholinguistic Approach. Edited by Frank Smith and G. A. Miller. Cambridge, Massachusetts and London: The M. I. T. Press. Pp. xii + 400. $4.

Acquisition du Langage at Developpement de la Pensee. By H. Sinclair-de Zwart. Paris: Dound. 1967. Pp. vi+ 168. 23F.

Principles and Methods of Social Psychology. By E. P. Hollander. London and New York: Oxford University Press. 1967. Pp. xxiii + 520. 64s.

Current Perspectives in Social Psychology. Second Edition. Edited by E. P. Hollander and R. G. Hunt. London and New York: Oxford University Press. 1967. Pp. vii + 685. 40s. (paper).

The Use of Lateral Thinking. By Edward de Bono. London: Cape. 1967. Pp. 157. 18s.

“Instinct” and “Intelligence”: The Science of Behaviour in Animals and Man. By S. A. Barnett. London: Macgibbon & Kee. 1967. Pp. xiv + 250. 45s.     

Variations in reflex blink-rate during visual-motor tasks

The influence of the performance of various tasks on the reflex blink rate has been investigated repeatedly, but the results obtained have been somewhat contradictory. More recently, it has been suggested that the reflex blink rate may be a considerable factor in the accuracy with which visual-motor tasks are performed. The aim of the present experiment was to attempt to obtain further evidence on both these questions.

The experiment was carried out in two parts. The main part was done in the laboratory, while a validating experiment was carried out on the road. In the laboratory, subjects were required t o steer a pencil along a moving track which varied in difficulty. The difficulty of the response was varied by using a direct control on some trials and a velocity control on others. Blink rate, errors, and control measurements were recorded throughout. In the road experiment, cine films were taken of the driver's eyes while driving in heavy traffic and in open country.

The results of both experiments show:

(a) That there are marked individual differences in blink rate, the relative order of which is maintained in spite of variations in the actual blink rate.

(b) That there is no relationship between the accuracy with which a particular individual carries out a task of this sort and his blink rate. The rapid “blinker” is no more and no less likely to be accurate than the infrequeiit I “blinker.”

(c) That the actual blink rate for all individuals varies inversely with the difficulty of the task and the amount of control movement necessary. The blink rate decreases as the necessity for detailed visual control of movement increases. Blink rates when driving a car in heavy traffic, or when steering along an oscillating track, are considerably lower than when driving in open country or when following a straight track.

(d) That the adjustment of the blink rate to the difficulty of the task is achieved not only by an alteration in overall blink rate, but also by a change in the distribution of blinking. The blink rate is approximately constant under constant conditions, but when the task is varying in difficulty, blinking occurs just before and just after periods of maximum difficulty, but is completely inhibited during the periods of maximum difficulty itself.     

Visual search without eye movement

Two experiments have been made on the problem of visual search using six patterns which were geometrically simple, and familiar to the subject.

In each case the subject's task was to say where, among the complex of patterns, a particular pattern (the “test object”) appeared when the exposure of the whole display was so brief as to prevent scanning by the eyes. He could be informed visually (in Experiment I) or verbally (in Experiment II) which pattern was to be regarded as the “test object.”

In both experiments it was found that foreknowledge of what was to be the test object gave a significantly higher standard of accuracy than knowledge given later. This suggests that something analogous to visual search can occur without eye movements.     

On the rate of gain of information

The analytical methods of information theory are applied to the data obtained in certain choice-reaction-time experiments. Two types of experiment were performed: (a) a conventional choice-reaction experiment, with various numbers of alternatives up to ten, and with a negligible proportion of errors, and (b) a ten-choice experiment in which the subjects deliberately reduced their reaction time by allowing themselves various proportions of errors.

The principal finding is that the rate of gain of information is, on the average, constant with respect to time, within the duration of one perceptual-motor act, and has a value of the order of five “bits” per second.

The distribution of reaction times among the ten stimuli in the second experiment is shown to be related to the objective uncertainty as to which response will be given to each stimulus. The distribution of reaction times among the responses is also related to the same uncertainty. This is further evidence that information is intimately concerned with reaction time.

Some possible conceptual models of the process are considered, but tests against the data are inconclusive.     

Early motion processes and the kinetic depth effect

It has been known for over 30 years that motion information alone is sufficient to yield a vivid impression of three-dimensional object structure. For example, a computer simulation of a transparent sphere, the surface of which is randomly speckled with dots, gives no impression of depth when presented as a stationary pattern on a visual display. As soon as the sphere is made to rotate in a series of discrete steps or frames, its 3-D structure becomes apparent. Three experiments are described which use this stimulus, and find that depth perception in these conditions depends crucially on the spatial and temporal properties of the display:

1. Depth is seen reliably only for between-frame rotations of less than 15°, using two-frame and four-frame sequences.

2. Parametric observations using a wide range of frame durations and inter-frame intervals reveal that depth is seen only for inter-frame intervals below 80 msec and is optimal when the stimulus can be sampled at intervals of about 40-60 msec.

3. Monoptic presentation of two frames of the stimulus is sufficient to yield depth, but the impression is destroyed by dichoptic presentation.

These data are in close agreement with the observed limits of direction perception in experiments using “short-range” stimuli. It is concluded that depth perception in the motion display used in these experiments depends on the outputs of low-level or “short-range” motion detectors.     

Book reviews and books received

In private practice Lenson, E. S., 1994 Succeeding in Private Practice: a Business Guide for Psychotherapists London, Sage ISBN 0-8039-4958-8 €19.50

Syme, G., 1994 Counselling in Independent Practice Buckingham, Open University Press ISBN 0-335-19049-9 €10.99

On families L'Abate, L. (Ed.) 1994 Handbook of Developmental Family Psychology and Psychopathology Chichester, Wiley ISBN 0-471-53527-3 €41.50

Telling tales and living lives Viney, L., 1993 Life Stories: Personal Construct Therapy with the Elderly Chichester, Wiley ISBN 0-471-93867-X €17.50

Freeman, M., 1993 Rewriting the Self: History, Memory and Narrative London, Routledge ISBN 0-415-04198-8 €11.99

Working with music Schalkwijk, F. W. (1994) Music and People with Developmental Disabilities: Music Therapy, Remedial Music Making and Musical Activities London, Jessica Kingsley ISBN 1-85302-226-8 €14.95

PSTD and storymaking Winn, L. (1994) Post-Traumatic Stress Disorder and Dramatherapy: Treatment and Risk Reduction, London, Jessica Kingsley ISBN 1-85302-183-0 €16.95     

Book reviews

Encyclopaedia of Linguistics, Information and Control. Edited by A. R. Meetham with the assistance of R. A. Hudson. Oxford: Pergamon Press. 1969. Pp. xiv + 718. 300s.

The Biological Basis of Personality. By H. J. Eysenck. Springfield: Thomas. 1968. Pp. xv + 399. $18.50.

Scientific Basis of Dvug Dependence. Biological Council Symposium. Edited by H. Steinberg. London: Churchill. 1969. Pp. 429. 100s.

Minnesota Symposia on Child Psychology, Vol. 2. Edited by John P. Hill. Minneapolis: University of Minnesota Press. 1969. Pp. viii + 172.

Memory and Attention: an introduction to human information processes. By Donald A. Norman. Chichester, Sussex: John Wiley. 1969. Pp. ix + 201. 84s. (cloth); 44s. (paper). Verbal Learning and Memory: selected readings. By Leo Postman and Geoffrey Keppel. Harmondsworth: Penguin Books. 1969. Pp. 501. 12s.

Handbuch der Kinderheilkunde. Edited by H. Opitz and F. Schmidt. Rand VIII/I: Neurologie-Psychologic-Psychiatrie. Redigiert von F. Schmidt und H. Asperger. Berlin: Springer Verlag. Pp. 1060. Price DM385, S96.25.

Digital Computing. By R. S. Lehman and D. E. Bailey. London: John Wiley & Sons Ltd. 1969. Pp. xxiv + 303. 79s.

Real-Time Computers. By W. R. Uttal. New York: Harper & Row. 1968. Pp. xiv + 338. 93s.     

Temporal factors in pattern vision

A sequence of uncorrelated randomly patterned visual stimuli (“visual noise”) is normally seen as a field of particles in “Brownian motion.” When each frame of the sequence is followed by a blank flash superimposed on the same region of the visual field, the apparent structure of the noise field is strikingly altered, its form varying with the time interval between frame and flash. At a critical interval, many dots seem to cohere, to form maggot-like objects.

Some of the factors determining this critical interval have been studied. They include the brightness, repetition frequency and exposure duration of the noise field, and the distance of its retinal image from the fovea.

The critical interval for “perceptual blanking” is quite different from that for the “maggot effect,” but the two show a suggestively similar dependence upon the duty cycle of the noise display.

It is of some neurological interest that the phenomenon is not appreciably visible with dichoptic mixing of noise and blank stimuli.     

Book reviews and books received

All in the mind Sanders, D., 1996 Counselling for Psychosomatic Problems London, Sage ISBN 0-8039-7922-3 €9.95

Designing counsellor training Dryden, W., Horton, I. & Mearns, D., 1995 Issues in Professional Counsellor Training London, Cassell ISBN 0-304-32978-9 €9.99

Training supervisors Carroll, M., 1996 Counselling Supervision: Theory, Skills and Practice London, Cassell ISBN 0-304-32983-X €12.99

Inskipp, F. & Proctor, B., 1995 The Art, Craft and Tasks of Counselling Supervision: Part 2, Becoming a Supervisor Twickenham, Middlesex, Cascade ISBN 09522758-2-1 €30

In-laws and outlaws Horsley, G.C., 1996 In-Laws: a Guide to Extended-Family Therapy Chichester, Wiley ISBN 0-471-12914-3 €27.50

Harway, M. (Ed.), 1996 Treating the Changing Family: Handling Normative and Unusual Events Chichester, Wiley ISBN 0-471-07905-7 €39.95     

Book reviews and books received

Bell, E., 1996 Counselling in Further and Higher Education Buckingham: Open University Press ISBN 0-335-19167-3 £12.99

Gersie, A. (Ed.), 1996 Dramatic Approaches to Brief Therapy London: Jessica Kingsley ISBN 1-85302-271-3 £16.95

Cowie, H.& Sharp, S., 1996 Peer Counselling in Schools: a Time w Listen London: David Fulton ISBN 1-85346-367-1 £12.99

Carroll, M., 1996 Workplace Counselling London: Sage ISBN 0-7619-5021-4 £12.95

Davies, D. & Neal, C., 1996 Pink Therapy Buckingham: Open University Press ISBN 0-335-19145-2 £16.99

Klass, D., Silverman, P.R. & Nickman, S.L. (Eds), 1996 Continuing Bonds New Understandings of Grief London: Taylor & Francis ISBN 1-56032-336-1 (hardback); 1-56032-339-6 (paperback) £30 (hardback): E17.95 (paperback)

JOHNS, H., 1996 Personal Development in Counsellor Training London: Cassell ISBN 0-304-32933-9 £12.99

Dryden, W. (Ed.), 1996 Research in Counselling and Psychotherapy: Practical Applications London: Sage ISBN 0-80-39-7841-3 £14.95     

Book reviews

Buckley, Key W. (1989). Mechanical man: John Broadeus Watson and the beginnings of Behaviorism. New York: Guilford Press. Pp. 293. ISBN 0-89862-744-3. $32.45/£18.00.

Colgan, P. (1989), Animal Motivation. New York and London: Chapman and Hall. Pp. 168. ISBN 0412-31850. £25.00 (hardback). ISBN 0412-31860, £10.95 (paperback).

Antinucci, F (Ed.) (1989). Cognitive structure and development in nonhuman prinates. Hillsdale, Nj: Laweence Erlbaum Associates, Inc. Pp. 266. ISBN 0-8058-0544. £16.50 (Hardback).

Parker, S.T. & Gibson, K.R. (Eds.) (1990). “Language” and intelligence in monkeys and apes. Cambridge: Cambridge University Press. Pp. 590. ISBN 0-521-38028-6. £40.00 (hardback).

Ley, Ronald (1990). A whisper of espionnage: Wolfgang Koehler and the apes of Tenerife. Garden City Park, NY: Avery Publoshing Corporation. Pp.264. ISBN 0-89529-432-x. $19.95.     

Book reviews and books received

Sexual abuse of clients Jehu, D., 1994 Patients as Victims: Sexual Abuse in Psychotherapy and Counselling Chichester, Wiley ISBN 0-471-94398-3 €17.95

Metaphor and imagery in therapy Cox, M. & Theilgaard, A., 1994 Shakespeare as Promoter: the Amending Imagination and the Therapeutic Process London, Jessica Kingsley ISBN 1-85302-159-8 €22.50

Student-centred study skills counselling Peelo, M., 1994 Helping Students with Study Problems Buckingham, Society for Research into Higher Education & Open University Press ISBN 0-335-19307-2 €12.99

A review of reviews Crown, S. & Freeman, H. (Eds), 1994 The Book of Psychiatric Books London, Jason Aronson ISBN 0-87668-510-6 €39.95

Counselling in Social Work Brearley.J., 1995 Counselling and Social Work Buckingham, Open University Press ISBN 0-355-19002-2 €10.99

Private practice McMahon, G., 1994 Setting Up Your Own Private Practice in Counselling and Psychotherapy Cambridge, National Extension College ISBN 1-85356-522-9 €24.95

Rational-emotive psychology Dryden.W., 1994 Invitation to Rational-Emotive Psychology London, Whurr ISBN 1-897634-51-6 €9.95     

Book reviews and books received

Ruth Holdsworth: Using Tests in Vocational Guidance. ICON Series 7. Stourbridge: Institute of Careers Officers, 1978. £3.50.

Students in Need: Essays in Memory of Nicholas Malleson. Guildford, Surrey: Society for Research into Higher Education, 1978. £5.50.

Sue Walrond-Skinner (ed.): Family and Marital Psychotherapy: a Critical Approach. London: Routledge & Kegan Paul, 1979. £4.75.

Stephen G. Weinrach: Career Counseling. New York: McGraw-Hill, 1979. £11.20.

Albert Mehrabian: Basic Behavior Modification. New Vistas in Counseling Series, Volume IX. New York: Human Sciences Press, 1978. £6.95.

Arnold Jennings: Management and Headship in the Secondary School. London: Ward Lock Educational, 1978. £7 hardback; £3.50 paperback.

Jean Rudduck: Learning through Small Group Discussion. Guildford: Society for Research into Higher Education, 1978. £4.20.

Ann Hurman: A Charter For Choice: a Study of Option Schemes. Windsor: NFER, 1978. £8.50.

R.D. Hinshelwood and Nick Manning (eds.): Therapeutic Communities: Reflections and Progress. London: Routledge & Kegan Paul, 1979. £5.50.

Bruce Hugman: Act Natural: a New Sensibility for the Professional Helper. London: Bedford Square Press, 1978. £3.95.

Bill Jordan: Helping in Social Work. London: Routledge & Kegan Paul, 1979. £4.95.

S.L. Garfield and A.E. Bergin: Handbook of Psychotherapy and Behavioral Change (2nd edition). New York: Wiley, 1978. £24.50.

Guy Neave: Research Perspectives on the Transition from School to Work. Amsterdam: Swets & Zeitlinger, 1978. 21.50 Dutch guilders.     

II Sensory feedback influences on keytapping motor tasks

Subjects were trained to tap a key continuously at a specific rate, and with a specific amount of pressure (regularity task). Performance of this task was studied under conditions of: (a) decreased auditory feedback (masking noise through earphones), (b) decreased visual feedback (tapping hand screened from view), (c) vibration (vibrators applied to forearm in order to “mask” proprioceptive feedback), (d) digital block of tapping finger, and (e) combination of all four conditions. Significant changes in rate and intensity of tapping resulted under conditions of decreased auditory feedback, vibration, and the combined condition.

In the second part of the study, the effects of different delayed sensory events on keytapping were examined. The five conditions of delayed sensory feedback were: (a) delayed auditory feedback, (b) delayed visual feedback, (c) delayed tactile feedback, (d) the first three delayed sensory events presented simultaneously, and (e) condition (d) repeated with digital block of the tapping finger.

The conditions of delayed sensory feedback did not markedly alter performance of the regularity task. The same conditions of delayed sensory feedback did, however, produce highly significant changes in the performance of a more complex pattern task. All of these delay conditions produced parallel changes in the pattern task, namely increased intensity and decreased rate of tapping. The fact that the pattern task is more disturbed by delayed sensory feedback than the regularity task suggests that temporal complexity of the task is one determinant of the degree to which it will be disturbed by a delay in sensory feedback.